need advice

ok i have kind of a dumb middle school queston lol. ok theres this girl i like she knoes i like her and everything (i told her)but w/e she doesnt fel the same for me but we r good friends. for some reason i feel like shes hidin her feeings fom me and i want to be sweet you kow what im saying? well today she looked beautiful in school and it was hard to even keepeye contact so after school i was like i shouldve told her she looked pretty today (i don want to get tointo it cuz i don wan her to think im flirting bu my question is shouldi tell her o u looked pretty today whni talk to her online today or should i sayo u looked pretty the other day when i see her in school or should i wait for another day like today andtell her there that she looks pretty? i hope i didnt mae this too confusing and know this is a childish question for someone y agebut if u hve any thoughts id like to hear them